Refracting errors

 To see clear, the cornea and a lens should incurvate — or to refract — easy beams, thus they concentrate on a retina — a stratum of cells feeling light which level an eye back. The retina converses easy beams to impulses which send to a brain where they admit as the image. If easy beams do not concentrate on a retina, the image which you see, is indistinct. It term as a refracting error. Points, contacts and refracting surgery try to reduce these errors at zastavlenii easy beams to concentrate on a retina.

 Refracting errors cause an eyeball insufficiently well having the shape, rogovitsoj or a lens, and have three basic types:

• Short-sightedness — a myopia; only the next objects are clear
  
• Hyperopia — a hyperopia; only objects are far clear
  
• Astigmatism — images are erased apart and nearby
  
• Presbyopia — "a growing old eye." The Condition usually meets between age 40 and 50, and can be corrected with bifocals or reading of points